Detectives investigating an explosion in New York which injured 29 people have found a 'pressure cooker'-type device in the nearby area, CNN has reported.

The broadcaster, citing law enforcement sources, said the device was connected to a mobile phone and had wires attached.

Police had earlier confirmed they had found a potential second explosive in 27th Street between 6th and 7th Avenues and were working to clear the "suspicious package".

A large cordon has been put in place while investigations are carried out.